The justices on Tuesday reversed a lower court ruling that blocked the state-court suit against AU Optronics Corp.

Justice Sonia Sotomayor, writing for the court, said the New Orleans-based 5th U.S. Circuit Court of Appeals was wrong to order that the case be tried in federal court.

The issue was whether the federal Class Action Fairness Act, aimed at taking class-action lawsuits from consumer-friendly state courts to more business-friendly federal courts, also applied to cases filed by a state on behalf of its residents.

Taiwan-based AU Optronics is one of several Asian companies sued for fixing prices for thin film transistor liquid-crystal display panels from 1999 to 2006.